Appendicular Muscles Flashcards
What are the three major characteristics of the appendicular musculature?
- Innervation: by spinal nerves forming plexuses, and cranial nerve 12 innervating trapezius
- Attachments: attachments on axial and appendicular skeleton
- Movements: muscle contraction causes limb segment to move in specific plane at given joint (with bones)
What are the major characteristics of the upper limb musculature?
Innervated by branches of the brachial plexus (C5-T1 of spinal cord) except the trapezius (CNXII, spinal accessory)
Four major muscle groups crossing upper limb joints: shoulder (pectoral girdle), arm, forearm, hand
What are the upper limb joints designed for? What are the major functions of the upper limb musculature?
Designed for mobility (reaching, throwing, grasping, manipulating)
Muscles positioning pectoral girdle
Muscles moving the arm
Muscles moving forearm and hand
Muscles moving hands and digits
What is the major muscle moving the pectoral girdle?
Trapezius: multiple actions, depends on fiber orientation (elevator, retractor and depressor of scapula)
Attaches at the vertebral column, back of head, subscapular spine (up to T12), crosses the scapulothoracic (joint)
What are the three muscle lying under the trapezius that assist in movement of the scapula?
Levator scapulae: elevates scapula (attach on VC)
Rhomboids: retractor of scapula to midline (attach on VC)
Serratus anterior: protractor of scapula (attach at ribs and
VC)
What muscles are involved when reaching up? How does the scapula move? What is the group name for these muscles?
Scapula rotates laterally (bottom) when reaching up, allowing arm to get fully overhead
Lower and upper fibers of trapezius pull up and down, and the serratus anterior moves down and lateral to move scapula outwards and hand reaches up
This is called a force couple
What muscle moves the arm at the shoulder joint and covers a large part of the chest?
Pectoralis major: arm abductor, flexor and medial rotator
Attaches at clavicle, sternum and ribs, can move so many ways because crosses ball and socket shoulder joint
What is the major arm abductor?
Deltoideus, right across shoulder joint, attaches at clavicle and acromion, crosses the shoulder joint anteriorly thus abducts very well
Can also be an arm flexor, and medial rotator (anterior)
What muscle lies under the pectoralis major and attaches on scapula?
Subscapularis crosses shoulder joint anteriorly to attach on humerus, crosses ball and socket joint
What large muscle covers much of lower ribs?
Latissimus dorsi (lats): powerful arm retractor, arm extensor, adductor, and medial rotator
What two muscle directly correspond to their fossa attachments and are located under pectoralis?
Supraspinatus: arm abductor, assists deltoid (synergist), and attached on supraspinous fossa of scapula, crosses shoulder joint at top
Infraspinatus: arm lateral rotator, attaches to infraspinous fossa on scapula, crosses shoulder joint posteriorly
What two major/minor muscles move the arm at the shoulder joint?
Teres minor: arm lateral rotator, same function as lats, with less force
Teres major: arm extensor, adductor, and medial rotator (assists lats)
What are the 4 rotator cuff muscles? What do they do?
SITs:
Supraspinatus, Infraspinatus, Subscapularis, Teres minor
Tendons of SITS muscles reinforce the shoulder joint capsule and hold the humeral head against glenoid fossa (prevents dislocation)
What are the two muscles that move the forearm at the elbow joint on the lateral side?
Brachialis: DEEP, main forearm flexor when pronated, attaches at ulna and flexes hinge joint
Brachioradialis: forearm flexor, attaches at lateral humerus used when mid-supination/ pronation position
What are the two brachii muscles and which is anterior/posterior?
Biceps brachii: anterior, two heads, short head near coracoid process and long head by glenoid process, attach at scapula and radius, powerful forearm supinator, flexor when supinated, arm flexor, crosses two joints, supination of forearm is main function
Triceps brachii: posterior, long and lateral heads, medial head is deep, forearm extensor (antagonist of bicep), all heads form 1 tendon
What is the anterior muscle group moving the hand at the wrist joint? Where do they attach? What structure does not attach at medial epicondyle?
Attach at medial epicondyle, this group are flexors
Flexor carpi radialis: hand flexor and abductor
Palmaris longus: weak hand flexor
Flexor carpi ulnaris: hand flexor and adductor
Flexor retinaculum: strong fibrous band forming roof of carpal tunnel
What are the anterior muscles moving the digits?
Flexor digitorum superficialis: finger flexor (digit 2,3,4,5)
Flexor digitorum profundus: under FGS, finger flexor (digits 2,3,4,5)
Flexor pollicis longus: thumb, pollux flexor
Each finger gets 2 tendons (3 phalanges) and the thumb gets 1(two phalanges)
What is the structure of the carpal tunnel and what is carpal tunnel syndrome?
Carpal tunnel contains median nerve and 9 flexor muscle tendons, with the flexor retinaculum forming the roof. Tendons are covered with sheath of synovial fluid to prevent friction.
Carpal tunnel is when repetitive motion of flexor tendons irritate sheath coverings leading to swelling and compression of median nerve in the carpal tunnel
What are the posterior muscles moving the hand at the wrist joint? Where do they attach?
Extensor carpi radialis longus and brevis: hand extensor and abductor
Extensor carpi ulnaris: hand extensor and adductor
They attach at the lateral epicondyle
What are the posterior muscles moving the digits? Where do they attach?
Extensor digitorum and extensor digiti minimi: finger extensors (digits 2,3,4,5)
Extensors and abductor for thumb (pollicis)
What are the muscles moving the digits in the palm that are visible anteriorly?
3 palmar interossei: finger adductors (digits 2,4,5, pointer, ring and pinkie, because middle at midline)
4 lumbricals: finger extensors (digits 2,3,4,5), small motor units therefore fine control
What are the 4 muscles involved in moving the thumb?
Adductor pollicis (thumb adductor)
Flexor pollicis brevis
Opponens pollicis
Abductor pollicis brevis
The last three muscles are the thenar muscles which are important to opposition of the thumb
What are the hand muscles so deep in the hand you can only see them posteriorly?
2 dorsal interossei: finger abductors (digits 2,3,4)
Middle finger gets two dorsal interossei, ring finger has its own abductor
What are the two different types of grip and what muscles are involved?
Power grip: active contraction of digital flexor muscles found in forearm( ex. flexor digitorum profundus)
Precision grip: active contraction of some short muscles found in the hand (ex. thenar muscles)
What are the major characteristics of the lower limb musculature?
Innervated by branches of the lumbosacral plexus (L2-S3)
Four major muscle groups crossing lower limb joints: hip (pelvic girdle), thigh, leg, foot
What are the lower limb joints designed for? What are their major functions?
Designed for stability (posture, locomotion, balance)
Muscles moving thigh
Muscles moving leg
Muscles moving foot/ toes
What are the three gluteus muscles moving the thigh at the hip joint?
Gluteus maximus: thigh extensor, lateral rotator, largest muscle in body, not used when you walk, crosses hip joint posteriorly
Gluteus medius: thigh abductor and medial rotator, used when walking, prevelts pelvis tilt
Gluteus minimus: thigh abductor and medial rotator, used when walking
What are the other two muscles besides the gluteus that move the thigh at the hip joint?
Iliopsoas: thigh flexor, most important, crosses hip joint anteriorly and attaches at lesser trochanter (stairs)
Adductor muscle groups: medial side of body, thigh adductor, flexor, medial rotator
What two muscles move the leg at the knee joint and lie above the knee?
Quadriceps femoris (3 vasti and rectus femoris): 4 parts huge muscle, leg extensor, thigh flexor (RF only), common tendon crosses at patella anteriorly (hinge)
Sartorius: thigh and leg flexor, lateral rotation
What three muscles make up the hamstring?
They attach at the hip bone and cross knee joint posteriorly, attach at ischial tuberosity
Semitendinosus (middle)
Semimembranosus (side)
Biceps femoris (long and short heads)
All three are leg flexors (and thigh extensors at the hip joint), dual action because they cross the hip and knee joint
What 3 muscles are involved as calf muscles that move the foot at the ankle joint?
Gastrocnemius and Soleus: powerful foot plantar flexors
Calcaneus (Achilles) tendon: attaches at calcaneus, crosses posteriorly on ankle joint (hinge)
What are the anterior muscles moving the foot at the ankle joint?
2 Peroneus (fibularis): foot evertors (lateral), also plantar flexors
Tibialis anterior: foot dorsiflexor and inverter, medial side
What are the muscles moving the digits on the anterior side of leg?
Extensor digitorum longus (digits 2,3,4,5): toe extensor
Extensor hallucis longus: big toe extensor
What are the muscles on the bottom of the foot? What muscles move the digits on posterior side of leg?
Flexor digitorum brevis : toe flexor (digits 2,3,4,5) shorter
Flexor digitorum longus: toe flexor (digits 2,3,4,5)
Flexor hallucis longus: big toe flexor
